Infusion device and inlet structure for same

ABSTRACT

An infusion device includes a disc-shaped housing that is made from a biocompatible material. The housing contains a reservoir for holding a volume of infusion medium, such as a medication to be administered to the patient. The inlet structure is coupled in flow communication with the reservoir, to allow the reservoir to be filled or re-filled. The housing has an outlet through which the infusion medium may be expelled. Any one or combination of aspects may be employed to minimize or reduce the required thickness T of the inlet structure and of the infusion device, including: the selection of a convergence angle of the cone-shaped depression to be within the range of about 60° and 180° and, preferably about 150°; a septum having one or more sealing ribs or a recess for receiving a support ring, to allow the septum to be made relatively thin without compromising sealing or support functions; a cup member having grooves and indentations formed in its inner surfaces, to improve flow of infusion medium without added structural thickness; a valve member having a relatively shallow needle-receiving depression or having a recess for receiving and sharing thickness with a the spring; and an inlet configuration which accommodates a needle having an opening located near its tip and, thus, employs a relatively short stroke of the valve member between closed and open states of the valve member.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] Embodiments of the present invention claim priority from a U.S.Provisional Application entitled “Infusion Device and Inlet StructureFor Same,” Serial No. 60/318,056, filed Sep. 7, 2001, the contents ofwhich are incorporated by reference herein.

FIELD OF THE INVENTION

[0002] The present invention relates generally to infusion devices,systems and processes and, in particular, embodiments to implantableinfusion devices systems and processes employing an inlet configurationfor minimizing the overall thickness dimension of the device. Furtherembodiments of the invention relate to inlet structures and processes ofmaking and using such inlet structures for infusion devices and systems.

RELATED ART

[0003] Infusion devices are typically used to deliver an infusion media,such as a fluidic medication or drug, to a patient. Such medication ordrug may be in the form of a liquid, gelatinous, particulate suspendedin a fluid, or the like. Implantable infusion devices are designed to beimplanted in a patient's body, to administer an infusion media to thepatient at a regulated dosage or infusion rate.

[0004] Because implantable infusion devices are designed to be implantedin the patient's body, the dimensions of such devices can have an impacton the location in the body at which the device may be implanted, thelevel of comfort of the implant patient and the external appearance ofthe implant site. Typically, a device with relatively small dimensionsand, in particular, a relatively small thickness dimension, will providegreater flexibility in the choice of location in the patient's body toplace the implant and will minimize patient discomfort and minimizenoticeable protrusions at the implant site. Accordingly, there is ademand in the industry for minimizing the overall dimensions, and, inparticular, the thickness dimension of implantable infusion devices.

[0005] An implantable infusion device may include a generallydisc-shaped housing having a diameter dimension and a thicknessdimension. The housing should be sealed to inhibit unwanted leakage toor from the device, when implanted. The thickness dimension of thehousing is dependent, at least in part, upon the relative placement ofdevice components within the housing and the thickness dimensions of thedevice components. Such device components typically include a reservoirlocated within the housing for holding a volume of an infusion medium,for example, a liquid medication. Such device components also typicallyinclude a driving mechanism, such as a pump, and an electronic circuitand power source for controlling the driving mechanism. The drivingmechanism may be controlled to cause the infusion medium to flow fromthe reservoir to the patient, through an outlet in the housing, eitheron a continuous basis, at scheduled or programmed times, or in responseto signals from a sensor or other signal source.

[0006] Infusion devices also may include an inlet structure forreceiving infusion medium into the reservoir to fill or re-fill thereservoir, for example, from a hollow needle, such as an hypodermicneedle. Inlet structures have been configured with conical-shaped portsdesigned to receive a needle and guide the tip of the needle into aninlet opening. Such inlet structures allow an implanted infusion deviceto be filled or re-filled by inserting a hypodermic needle through thepatient's skin at the implant site, and into the inlet port of implanteddevice. An infusion medium may then be dispensed from the hypodermicneedle into the implanted device, or drawn from the implanted deviceinto the needle. In this manner, the reservoir in the implanted devicemay be filled or refilled to increase the operational life of theimplanted device. However, to effectively operate over multiplere-filling procedures, the implanted device must be capable of selfsealing during and after repeated re-fill procedures.

[0007] The conical-shaped port of typical inlet structures, as well asother components of the inlet structure that provide the sealingcapabilities noted above, contribute to the thickness dimension of theinlet structure and, thus, may also contribute to the overall thicknessdimension of the infusion device. Accordingly, there is a further demandin the industry for an implantable device and inlet structure that notonly has a minimized thickness dimension, but also has an inlet port andsealing mechanism that allows repeated re-filling and re-sealingprocedures. In addition, because the length of time between re-filloperations is dependent, at least in part, on the volume capacity of thereservoir of the infusion device, there is a further demand in theindustry for an implantable device having an inlet structure that doesnot displace volume in the reservoir section of the device.

[0008] Example implantable infusion devices are described in U.S. Pat.No. 5,514,103 and U.S. Pat. No. 5,176,644, each to Srisathapat et al.(and assigned to Minimed Technologies, Ltd.), U.S. Pat. No. 5,167,633 toMann et al. (and assigned to Pacesetter Infusion, Ltd.), U.S. Pat. No.4,697,622 to Swift (assigned to Parker Hannifin Corporation) and U.S.Pat. No. 4,573,994 to Fischell et al. (assigned to The Johns HopkinsUniversity), each of which is incorporated herein by reference. Each ofthe above-cited patents describes an implantable infusion device whichincludes a generally disc-shaped housing containing a reservoir, adriving mechanism or pump, an inlet structure, an outlet and anelectronic circuit for controlling the operation of the drivingmechanism.

[0009] U.S. Pat. No. 4,573,994 (“the '994 patent”) describes an inletstructure for an implantable infusion device, where the inlet structureincludes a cone-shaped inlet port that is sealed by a septum. In oneinlet example described in the '994 patent, a pressure activated valvecouples the chamber below the septum to the device reservoir. Thus, anexternal pressure must be applied to the infusion medium received in theinlet, to allow the medium to pass the pressure operated valve. Inanother example described in the '994 patent, an inlet structureincludes a cone-shaped inlet port and a moveable, cup-shaped poppetvalve positioned below a septum. The cup-shaped poppet valve isconfigured deep enough to receive a length of a standard hypodermicneedle, from the needle tip to a portion of the needle shaft above theopening. The depths of the cone-shaped inlet port and of the cup-shapedpoppet valve contribute significantly to the thickness dimension of theinlet structure and, thus, may contribute to the thickness dimension ofthe overall infusion device.

[0010] U.S. Pat. No. 4,697,622 (“the '622 patent”) also describes aninlet structure for an implantable infusion device, where the inletstructure includes a relatively deep, conical-shaped port or needleguide and a relatively deep poppet valve. The depth of the conicalshaped port and the depth of the poppet valve both contributesignificantly to the thickness dimension of the inlet structure. Inaddition, the inlet structure described in the '622 patent includesfurther components, such as an annular band and a seating ring, disposedbetween the septum and the poppet valve, which also contribute to thethickness dimension of the inlet structure.

[0011] Thus, notwithstanding the above example inlet structures, thereremains a demand in the industry for new and improved infusion deviceconfigurations and inlet structures having reduced thickness dimensions,yet which do not compromise other operational characteristics, such asthe capability to allow multiple re-fill and re-seal operations and theease at which a re-fill operation may be carried out.

SUMMARY OF THE DISCLOSURE

[0012] The present invention relates generally to infusion deviceshaving inlet structures. Particular embodiments relate to inletstructures for such devices and methods of making and using the same,which address one or more of the concerns and demands in the industry asnoted above.

[0013] Embodiments of the present invention employ inlet structures thatreduce the thickness requirements of the device, as compared to priorinlet structure configurations. In this manner, an infusion device maybe formed with a relatively thin housing, without compromising the inletoperation of the device. More specifically, preferred embodimentsprovide an infusion device and an inlet structure for an infusion devicewith a relatively small thickness dimension, but without compromisingsealing capabilities, fill and re-fill capabilities, and capabilitiesfor multiple re-filling operations to improve the operational life spanof the device. Various preferred embodiments are particularly suited forimplant environments. Other preferred embodiments may be employed inexternal (non-implant) environments.

[0014] An infusion device according to an embodiment of the inventionincludes a generally disc-shaped housing that is made from abiocompatible or biostable material and/or coated with an appropriatebiostable or biocompatible material. The housing contains a reservoirfor holding a volume of medium, such as, but not limited to, amedication to be administered to the patient, a testing medium, acleaning medium, or the like. An inlet structure is coupled in flowcommunication with the reservoir, to allow the reservoir to be filled orre-filled. In some embodiments, the inlet structure also may be used toremove or draw medium from the reservoir, for example to empty or flushthe reservoir, or to sample or test the medium from the reservoir.

[0015] Medium may be added to or drawn from the reservoir by inserting aneedle, such as an hypodermic needle, into the inlet and expellingmedium from or drawing medium into the needle. In some embodiments, thereservoir is under a negative pressure relative to the pressure of inthe external environment (the environment outside of the patient'sepidermis). In this manner, during a fill or re-fill operation, thenegative pressure within the reservoir may be used to draw or help drawinfusion medium from the needle. In preferred embodiments, the negativepressure of the reservoir is sufficient to draw medium from the needleinto the reservoir, without requiring an additional external force to beapplied to the medium. In other embodiments, an external force, such asthe force of an hypodermic needle plunger, may be imparted on mediumwithin the needle, to convey or help convey the medium from the needleto the reservoir during a fill or re-fill operation. In furtherpreferred embodiments, the reservoir pressure is negative relative tothe implant environment (the environment within the patient's body, atthe implant site), to help reduce the risk of undesired leakage ofmedium from the reservoir, into the surrounding implant environment.

[0016] The housing has an outlet through which the infusion medium maybe expelled in a controlled fashion. The reservoir is coupled in fluidflow communication with the outlet. In some embodiments, a drivemechanism may be coupled in fluid flow communication with the reservoir,to drive infusion fluid out of the reservoir, through the outlet. Inother embodiments, medium may be forced from the reservoir by a positivepressure applied to the reservoir (or a positive pressure differentialbetween the reservoir and the outlet), in which case, delivery of mediummay be controlled or limited by the outlet configuration, an outletcatheter configuration, capillary resistance or the like. Alternatively,medium may flow or be drawn from the reservoir by other suitable means.

[0017] Embodiments of the invention may employ any one or combination ofaspects described herein for minimizing or reducing the requiredthickness dimension T_(I) of the inlet structure and, preferably, forminimizing or reducing the contribution of the inlet structure to theoverall thickness dimension T of the infusion device. In one preferredembodiment, all aspects described herein are employed to result in aninlet structure or infusion device with a relatively small thicknessdimension.

[0018] According to one aspect of the invention, the inlet structureincludes a cap member provided with a generally cone-shaped depressionfor contacting and guiding a needle into an inlet opening, during a fillor re-fill procedure. The cone-shaped depression defines an angle ofconvergence that is selected to be within the range of about 60° and180° and, preferably about 150°. An angle of convergence within theabove range and, preferably about 150°, provides sufficient needleguiding functions, yet does not require a depression thickness T_(D) aslarge as various prior inlet configurations.

[0019] According to another aspect of the invention, the inlet structureincludes a septum configured to provide sealing functions, yet withoutrequiring a significant contribution to the overall thickness T_(I) ofthe inlet structure. In preferred embodiments, the septum may have oneor more sealing ribs to assist in providing sealing functions withoutrequiring additional structural thickness. In further preferredembodiments, the septum may be made relatively thin and may be abuttedagainst a rigid support member, such as a rigid, annular support ring,to improve the structural strength of the septum without requiringsignificant septum thickness T_(S) to provide such structural strength.In yet further preferred embodiments, the septum is provided with arecess in which the support member is disposed, so that the septumshares at least a portion of the thickness dimension of the supportmember.

[0020] In some preferred embodiments, the septum includes a surfacewhich forms a valve seat for a moveable valve structure, such that theseptum and valve seat are provided as a single, unitary structure. Inalternative preferred embodiments, a separate valve seat member isdisposed within a recess provided in the septum, to minimize the overallthickness requirements of the septum and valve seat combination and/orto provide additional support for the septum.

[0021] According to a further aspect of the invention, the inletstructure includes a cup member having grooves and indentations formedin its inner surfaces, to improve flow of infusion medium without addedstructural thickness.

[0022] According to yet a further aspect of the invention, the inletstructure is provided with a moveable valve member having a relativelyshallow depression for receiving the tip of a needle during a filling orre-filling procedure. The needle-receiving depression in the valvemember may have a depth within the range of about 0.010 inch and about0.050 inch. In preferred embodiments, the inlet structure is configuredto function as a part of a system which includes a needle having arelatively short length between the needle tip and the needle opening.With the use of such a needle, the thickness dimension of the portion ofthe inlet structure that contains the moveable valve member may bereduced, by allowing the depth of the needle receiving depression to bereduced and/or the length of the maximum stroke of movement which thevalve member must move during a fill or re-fill procedure to be reduced.

[0023] According to yet a further aspect of the invention, the inletstructure includes a septum that also functions to provide a valve seatfor an inlet valve. In this manner, a separate valve seat element is notnecessary and the additional complexity, cost and thickness thatotherwise would have been contributed by a separate valve seat elementmay be avoided.

[0024] These and other aspects and advantages of the invention will beapparent to one of skill in the art from the accompanying detaileddescription and drawings. Each of the above-noted aspects of theinvention, as well as other aspects of the invention, may be practicedseparately or in various combinations.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Referring now to the drawings in which like reference numbersrepresent corresponding parts throughout:

[0026]FIG. 1 is a perspective view of an implantable infusion deviceaccording to an embodiment of the invention.

[0027]FIG. 2 is a perspective view of an inlet structure for animplantable infusion device according to an embodiment of the invention.

[0028]FIG. 3 is a partial exploded view of the device of FIG. 1, withthe inlet structure of FIG. 2.

[0029]FIG. 4 is a cross-section view of the inlet structure of FIG. 2,where the valve member is in a closed state.

[0030]FIG. 5 is a partial exploded view of the inlet structure of FIGS.2 and 4.

[0031]FIG. 6 is a cross-section view of an outer cap of the inletstructure of FIGS. 2 and 4.

[0032]FIG. 7 is a cross-section view of a cup member of the inletstructure of FIGS. 2 and 4.

[0033]FIG. 8 is a top view of the cup member of FIGS. 2 and 4.

[0034]FIG. 9 is a cross-section view of a septum of the inlet structureof FIGS. 2 and 4.

[0035]FIG. 10 is a cross-section view of a valve member of the inletstructure of FIGS. 2 and 4.

[0036]FIG. 11 is a cross-section view of a portion of the inletstructure of FIG. 2, with a needle entering the inlet opening and thevalve member in a closed state.

[0037]FIG. 12 is a cross-section view of a portion of the inletstructure of FIG. 2, with a needle passed through the septum and thevalve member moved to an open state.

[0038]FIG. 13a is a side view of a needle according to an embodiment ofthe present invention and for use with an inlet structure according toan embodiment of the present invention.

[0039]FIG. 13b is a side view of a conventional needle.

[0040]FIG. 14 is a cross-section view of an inlet structure according toanother example embodiment of the present invention.

[0041]FIG. 15 is an exploded perspective view of the inlet structure ofFIG. 14.

[0042]FIG. 16 is a cross-section view of an inlet structure according toyet another example embodiment of the present invention.

[0043]FIG. 17 is an exploded perspective view of the inlet structure ofFIG. 16.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0044] This description is not to be taken in a limiting sense, but ismade merely for the purpose of illustrating the general principles ofexample embodiments of the invention. The scope of the invention is bestdefined by the appended claims.

[0045] As discussed above, embodiment of the present invention relatesgenerally to infusion devices systems and processes employing inlets,and to inlet structures for such devices and systems. Variousembodiments and features described herein may be employed in implantableor external infusion devices. However, certain preferred embodiments ofthe invention relate to such devices and inlet structures configuredwith a minimized thickness dimension, for example, to minimize trauma tothe implant recipient (referred to herein as the patient), to improvethe flexibility in selecting implant sites and/or to improve theexternal appearance of the implant site. The term “patient” is intendedto refer to the entity in which the implantable devices are implanted,whether or not the implant is carried out for medical purposes.Accordingly, the term “patient” is not to be construed as a reference orlimitation to a medical context.

[0046]FIG. 1 shows an implantable infusion device 10, according to anembodiment of the invention. The illustrated device 10 is configured tobe surgically implanted into a patient. The device 10 includes agenerally disc-shaped housing 12 that is made from or coated with asuitable biocompatible or biostable material. As described above, otherembodiments may be employed in external (non-implant) and/or non-medicalenvironments, where the housing 12 need not be biocompatible orbiostable.

[0047] The housing 12 of the FIG. 1 has a diameter dimension D, definingthe diameter of the disc shape, and a thickness dimension T, definingthe overall thickness of the device. While FIG. 1 shows a circulardisc-shaped embodiment, it will be understood that further embodimentsof the invention may employ housings of other shapes, including, but notlimited to, oval, oblong, rectangular, or other curved or polygonalshapes. Because the device is designed to be implanted in a patient'sbody, it is typically preferable that all edges, corners and the like berounded or smoothed to avoid irritating tissue at the implant site. Itis also typically preferable to minimize the overall dimensions of thehousing 12 and, in particular, the thickness dimension T.

[0048] The housing 12 includes a reservoir housing portion 13 containinga reservoir for holding a volume of a medium, for example, but notlimited to, an infusion medium such as a medication to be administeredto the patient, a testing medium or a cleaning medium. The housing 12includes a further housing portion 14, shown above the reservoir housingportion 13 in FIG. 1. Representative examples of reservoir housingportions and reservoirs which may be employed in embodiments of theinvention are described in co-pending U.S. Patent Application Serial No.60,317,880 (attorney docket no. 047711.0202), titled “ImplantableInfusion Device And Reservoir For Same,” which is incorporated herein byreference. However, further embodiments may employ other suitablereservoir configurations, including, but not limited to, those describedin U.S. Pat. No. 5,514,103 and U.S. Pat. No. 5,176,644, each toSrisathapat et al, U.S. Pat. No. 5,167,633 to Mann et al., U.S. Pat. No.4,697,622 to Swift and U.S. Pat. No. 4,573,994 to Fischell et al.

[0049] The housing 12 also has an outlet 15 through which the infusionmedium may be expelled. When the device 10 is implanted in a patient, acatheter may be connected to the outlet 15 to deliver infusion mediumexpelled from the outlet 15 into the patient's blood stream or to aselected location in the patient's body. A drive mechanism 16, such as apump, and an electronic control system 18 may be included in the portion14 of the housing. In preferred embodiments, the drive mechanism 16comprises a structure as described in co-pending U.S. Patent ApplicationSerial No. 60/317,886, titled “Infusion Device and Driving Mechanism ForSame,” filed Sep. 7, 2001 under attorney docket no. 0204 (assigned tothe assignee of the present invention), which is incorporated herein byreference. The drive mechanism 16 is connected between the reservoir andthe outlet 15. The electronic control system 18 includes a power source,such as a battery, and electronics for controlling the drive mechanism16 to deliver infusion medium from the reservoir, to the patient in aselected manner, for example, according to a programmed dispensing rateor schedule.

[0050] In one embodiment, the portion 14 of the housing 12 that containsthe drive mechanism 16 and control electronics 18 is hermetically sealedfrom the external environment and from the reservoir housing portion 13,while the reservoir housing portion 13 need not be hermetically sealed.In such an embodiment, the portion 14 of the housing containing thedrive mechanism 16 and control electronics 18 may be made from titaniumor titanium alloy, other metals, ceramics or other suitable biostable orbiocompatible materials, while the reservoir portion 13 of the housingmay be made from such materials or from a biostable or biocompatibleplastic.

[0051] The infusion device 10 includes an inlet structure 20 whichprovides a closeable and sealable fluid flow path to the reservoirportion 13 of the housing. The inlet structure provides a port forreceiving a needle through which fluid may be transferred to theinfusion device, for example, to fill or re-fill the reservoir of thedevice. In preferred embodiments, the inlet structure is configured tore-seal after a fill or re-fill operation, and to allow multiple re-filland re-seal operations.

[0052] As described above, the inlet structure can contribute to theoverall thickness dimension T of the infusion device 10. Accordingly,preferred embodiments of the present invention relate to and employinlet structures that reduce the thickness requirements of the device.In this manner, embodiments of the present invention may employ thinnerhousings, as compared to prior infusion device configurations.

[0053] The ability to reduce or minimize the device thickness dimensionT, without compromising the inlet capabilities, can provide significantadvantages with respect to patient comfort, appearance, flexibility inselecting implant locations on the body. Accordingly, inlet structuresthat allow for reduced or minimized device thickness dimensions, asdescribed herein, may provide significant advantages in the implantableinfusion device technology.

[0054]FIG. 2 shows an inlet structure 20 according to an embodiment ofthe present invention. In the illustrated embodiment, the inletstructure 20 has a generally cylindrical outer surface 22 and two ends(an upper end and a lower end when oriented as shown in FIG. 2). Theupper end in FIG. 2 has an inlet opening 24 at the apex of a cone-shapeddepression 26. The bottom end in FIG. 2 has a lip 28 extending outwardand around the circumference of the inlet structure.

[0055] The inlet structure 20 of FIG. 2 may be configured to be part ofan assembly of components that, when assembled, form the infusion device10 of FIG. 1. FIG. 3 is a partially exploded view of the infusion device10, showing the location of the inlet structure 20 within the assembly.The assembly also includes the reservoir portion 13 and the furtherportion 14 of the housing 12.

[0056] The reservoir housing portion 13 includes an interior 30 forcontaining a reservoir structure (not shown) to hold a volume ofinfusion medium, such as, but not limited to, medication, a testingmedium, a cleaning medium or the like. The reservoir housing portion 13also includes a cover 32 composed of a disc-shaped member having acircular, central opening 34. The opening 34 has a diameter of about, orslightly larger than, the diameter of the outer surface 22 of the inletstructure 20, but smaller than the outer diameter of the lip 28 of theinlet structure. The inlet structure 20 is configured to fit within theopening 34, as shown in FIG. 4.

[0057]FIG. 4 shows a cross-section view of the inlet structure 20,assembled with the cover 32 (partially illustrated). As shown in FIG. 4,when the inlet structure 20 is assembled with the cover 32, the lip 28of the inlet structure is located on the reservoir side of the opening34, while the majority of the inlet structure is located on the oppositeside of the opening (outside of the reservoir housing portion 13).

[0058] The reservoir side of the cover 32 may be provided with anannular recess 40, in which the lip 28 may sit. In the illustratedembodiment the recess 40 has a circumference that is slightly largerthan the circumference of the lip 28 and has a depth that is slightlylarger than the thickness of the lip 28, such that the lip 28 fitscompletely within the recess 40. As a result, the bottom end of theinlet structure 20 in FIG. 4 is generally flush with or inset from thebottom surface of the cover 32. In further embodiments, inlet 20 may beformed without lip 28 and/or cover 32 may include one or more smallapertures (instead of opening 34 for allowing fluid flow between theinlet and the reservoir within the housing portion 13. In preferredembodiments, however, the inlet structure requires minimal or no spacewithin the reservoir housing portion 13, allowing maximum use of theinternal volume of the reservoir housing portion for containing infusionmedium, reservoir components and, in some embodiments, a propellantmedium.

[0059] In the illustrated embodiment, the inlet structure 20 comprisesan assembly of components shown in a partially exploded view in FIG. 5.With reference to FIGS. 4 and 5, the inlet structure 20 comprises anouter cap 42, a cup-shaped member 44, a septum 46, a support ring 48, avalve member 50, a spring 52, and a filter member 54.

[0060] The outer cap 42 of the inlet structure is shown incross-section, in FIG. 6. The cap 42 may be made of or coated with anysuitable biostable or biocompatible material, such as, but not limitedto, titanium, titanium alloy, stainless steel, ceramic, glass, plastic,or the like. The cap 42 comprises a generally rigid cylindrical bodywhich defines the generally cylindrical shape of the inlet structure,including the outer surface 22 and the lip 28 of the inlet structure.

[0061] The cap 42 also defines the generally cone-shaped depression 26and the opening 24 of the inlet. In particular, the generallycone-shaped depression 26 is provided in one end of the cap 42, whilethe lip 28 is provided at the opposite end of the cap. The diameter ofthe inlet opening 24 is selected to be slightly larger than the maximumdiameter of the needle used to fill or refill the reservoir. In oneembodiment the diameter of the inlet opening 24 may be any diameterwithin the range of about 12 to about 30 gauge and, in preferredembodiments, is about 0.31 of an inch.

[0062] The shape of the depression 26 is selected to provide a needleguiding function, to help guide a needle into the inlet opening 24. Inaddition, the shape of the depression may be selected to reduce orminimize the overall thickness T_(I) required by the inlet structure 20.In the illustrated embodiment, the generally cone-shaped depression 26has a straight wall, shown as straight lines in the cross-section viewof FIG. 6, which defines a cone-shape having an angle of convergence. Infurther embodiments, the cone-shaped depression 26 may have a curvedwall, defining an angle of convergence that is different at differentdiameters of the depression, for example a wall defining a curve whichdecreases or increases in convergence angle with increasing distancesfrom the inlet opening 24. In yet further preferred embodiments, thedepression includes an abrupt drop defining an annular wall 25 at theouter perimeter of the depression, for providing a stop surface toinhibit a needle from sliding out of the depression 26, once the needlehas found the depression.

[0063] As the angle of convergence of the depression 26 affects thethickness dimension T_(D) of the depression 26, which, in turn, cancontribute to the overall thickness T_(I) of the inlet structure 20, anembodiment of the invention employs a depression 26 selected to minimizethe thickness T_(D), for example, having an angle of convergence (or anaverage angle of convergence) within the range of about 60° and about180° and, preferably, about 150°. An angle of convergence within theabove range and, preferably about 150°, provides sufficient needleguiding functions, yet does not require a thickness T_(D) as large asvarious prior inlet configurations. In one preferred embodiment, thediameter of the depression 26 is selected to be about 0.4 inch and astraight angle of convergence is selected to be about 150°, such thatthe thickness T_(D) is about 0.05 inch.

[0064] With reference to FIG. 6, the cap 42 has a hollow interior 60 anda threaded inner wall 62 surrounding the interior 60. The inlet opening24 provides an open passage extending from the center of the depression26, to the interior 60, through which a needle may pass, for example,during a fill or re-fill operation. The inner wall 62 is threaded toallow engagement with opposite facing threads on the outer surface ofthe cup member 44, when assembled as in FIG. 4. The cap 42 and the cupmember 44 may be assembled together in a screw-threading manner, byengaging the threaded walls of the two components and rotating onerelative to the other about the axis A (as shown in FIG. 5).

[0065] The cap 42 may be provided with a means for engaging a tool tohelp rotate the cap and cup member relative to each other about its axisA. In the illustrated embodiment, such tool engagement means includes apair of indentations 64 at the outer peripheral edge of the cap end, atdiametrically opposite sides of the axis A. In further embodiments, asingle indentation or more than two indentations may be employed. In yetfurther embodiments, one or more indentations may be located in othersuitable locations on the cap 42. The indentation(s) is (are) configuredto engage one or more correspondingly shaped and placed tines or ribs ona rotatable tool (not shown). In yet further embodiments, an indentationforming a cross shape, star shape or slot shape may be located on thedepression surface and centered relative to the axis A, for engaging ascrew-driver or similar tool having a cross (for example, Phillipsstyle), star or standard head. Similarly, in yet further embodiments,the cap 42 may be provided with one or more ribs, tines, cross, star orslot-shaped protrusions which engage one or more correspondingly shapedindentations in a rotatable tool (not shown). Once engaged, the tool maythen be rotated (or held stationary while the cup member 44 is rotated)to, for example, assemble, disassemble or adjust the connection betweenthe outer cap 42 and the cup member 44.

[0066] The cup member 44 of the inlet structure 20 is shown incross-section in FIG. 7 and as a top view in FIG. 8. The cup member 44may be made from or coated with any suitable infusion medium compatiblematerial. In embodiments in which the cup member 44 may come in contactwith bodily fluids or tissue, the cup member may be made of or coatedwith a suitable biostable or biocompatible material, such as, but notlimited to, titanium, titanium alloy, stainless steel, ceramic, glass,plastic or the like. The cup member 44 comprises a generally rigidcup-shaped body, having a generally hollow interior 70 and a threadedouter surface 72. The threaded outer surface is configured to engage thethreaded inner wall 62 of the cap 42, as described above. The interiorsurface of the end of the cup member 44 includes a number of apertures74, an annular groove 76, an annular raised portion 78 around the groove76 and a central portion 80 surrounded by the annular groove 76.

[0067] The apertures 74 provide a passage through which infusion mediumor other material from a needle may pass through the inlet structure 20,to fill or re-fill the reservoir of infusion device 10 (FIGS. 1 and 3).In some embodiments, the apertures 74 also allow communication of mediumout from the reservoir, through the inlet structure 20, for example, toempty or flush the reservoir. In the illustrated embodiment, cup member44 has eight, evenly spaced apertures 74, each at 45° angles relative toadjacent apertures. However, other embodiments may employ any suitablenumber of apertures greater or fewer than the eight, in any suitablepattern, including a single aperture pattern. However, multipleapertures in an evenly spaced pattern are preferred, to provide suitableflow volume for more quickly transferring infusion medium and minimizinglocations within the cup member in which infusion medium may be trapped.An evenly spaced pattern of apertures 74 may also help to more uniformlyburden the filter element 54, described below.

[0068] The apertures 74 may be connected by one or more grooves, such asannular groove 82 (shown in FIG. 8), to form one or more channelsconnecting the apertures. The annular channel formed by the groove 82improves distribution and flow of infusion medium to the apertures 74.In the illustrated embodiment, the apertures 74 are located adjacent theinner wall 84 of the cup member 44. The inner wall 84 may also includean indentation 86 adjacent each aperture 74, in fluid flow communicationwith the adjacent aperture 74, to further improve the flow efficiency ofthe structure.

[0069] When the inlet structure 20 is assembled as shown in FIG. 4, theraised portion 78 provides an annular surface which abuts the innerperipheral surface of the filter member 54. An annular surface 88surrounds the raised portion 78, for abutting one end of the filtermember 54. The groove 76 contains and retains a portion of the spring 52and the central portion 80 has a surface facing the valve member 50. Inone embodiment, the valve-facing surface of the central portion 80provides a stop member for contacting and stopping the movement of thevalve member 50 at the end of its open stroke. In other embodiments, thetension of the spring 52 is selected to be great enough to inhibitcontact between the valve member 50 and the surface of the centralportion 80 during normal fill or re-fill operations, for example, tominimize damage to any infusion media that may be in the space betweenthe central portion 80 and the valve member 50.

[0070] The septum 46 is shown in cross-section in FIG. 9. The septum maybe composed of any suitable biostable or biocompatible and infusionmedium compatible material capable of being pierced by a needle, forminga seal around the needle during a fill or re-fill operation, andresealing after removal of the needle. Suitable septum material mayinclude, but is not limited to polymers such as silicon rubber, ethylanepropylene, neoprene, latex, Teflon, or the like. The septum may beprovided with a centrally located slit (not shown), for assisting thepassage of the needle through the septum material.

[0071] With reference to FIGS. 5 and 9, the septum 46 comprises a round,disc-shaped member that has an annular recess 90 around its periphery.The annular recess 90 defines a central portion 92 which is thicker thanthe peripheral portion 94 of the septum. The thickness T_(S) at thecentral portion 92 of the septum is selected to provide a suitable sealagainst a needle passing through the septum during access operations(such as a fill, re-fill or fluid withdrawal operations) and a re-sealafter removal of the needle, preferably, a specified minimum number ofrepeated times.

[0072] The support ring 48 is configured to fit within the annularrecess 90 of the septum 46, as shown in FIG. 4. The support ring 48 maybe made of or coated with any suitably rigid, infusion medium compatiblematerial such as, but not limited to, titanium, titanium alloy,stainless steel, ceramic, glass, polymer or the like. When locatedwithin the recess 90, the support ring 48 provides structural supportand rigidity to the septum 46. In this manner, the septum 46 may be madewith a relatively small overall thickness T_(S), without compromisingstructural rigidity. In other words, the thickness T_(S) of the septumneed not be increased beyond the thickness needed to provide the sealingfunction described above. Accordingly, the contribution of the septumthickness T_(S) to the overall thickness T of the inlet structure may beminimized.

[0073] In the illustrated embodiment, the support ring 48 and theannular recess 90 are dimensioned such that the support ring fitscompletely within the recess 90. In this manner, the thickness T_(S) ofthe central portion 92 of the septum defines the overall septumthickness. In other embodiments, the support ring 48 may extend beyondthe thickness of the central portion 92, when placed in the recess 90.

[0074] The septum 46 may be provided with annular ribs 96, 98 and 100,and one or more peripheral ribs 102 for assisting in the sealingfunction of the septum. When assembled as shown in FIG. 4, the annularrib 96 may engage and be received within a corresponding annular groovein the inner surface of the end of the cap 42. In yet alternativeembodiments, the inner surface of the end of the cap 42 may be providedwith an annular protrusion for engaging and deforming a portion of theseptum 46 or being received within a corresponding, annular groove inthe septum 46.

[0075] The annular rib 98 is positioned to engage the support ring 48,to improve the seal between the septum 46 and the support ring 48. Theannular rib 100 is positioned to engage the valve member 50, when thevalve is closed, to improve the seal between the septum 46 and theclosed valve member 50. The peripheral rib 102 may be positioned toengage and be received within a corresponding annular groove 108 in theinner wall 84 of the cup member 44. In yet alternative embodiments, theinner wall 84 of the cup member 44 may be provided with an annularprotrusion for engaging and deforming a portion of the peripheral edgeof the septum 46 or being received within a corresponding, annulargroove in the peripheral edge of the septum 46.

[0076] In further embodiments, the ribs 96-102 may engage generallysmooth surfaces of the cap 42, cup member 44 and valve member 50,instead of engaging correspondingly shaped grooves in those surfaces. Insuch embodiments, the ribs 96-102 may be forced against the generallysmooth surfaces and partially deform against those surfaces to improvethe seal between the septum and those surfaces.

[0077] Thus, in the above-described embodiments, the annular andperipheral ribs 96-102 improve the sealing function of the septum 46,without significantly increasing the overall thickness T_(S) of theseptum. Moreover, the peripheral rib 102 improves the seal of the septumagainst cup member 44, without requiring a thicker peripheral septumedge and, thus a wider septum thickness T_(S) for increased sealingsurface area contact. Accordingly, the annular and peripheral ribsprovide yet a further mechanism for minimizing or reducing thecontribution of the septum thickness T_(S) to the overall thickness T ofthe inlet structure 20.

[0078] The valve member 50 is shown in cross-section in FIG. 10. Thevalve member 50 may be made of or coated with any suitable infusionmedium compatible material such as, but not limited to, titanium,titanium alloy, stainless steel, ceramic, glass, polymer, or the like.With reference to FIGS. 5 and 10, the valve member 50 has a generallyrigid, circular disc-shaped body, with an annular recess 104 around theperipheral edge of one side face of the body. The recess 104 defines acentral portion 106 which is thicker than the peripheral portion 108 ofthe valve member.

[0079] A depression 110 is provided in the opposite side face of thevalve member body, relative to the face having the annular recess 104.The depression side of the valve member body has an annular surface 112around the depression. The depression 110 provides a seat for a needlethat has passed through the septum, for example, during a fill, re-fillor fluid withdrawal operation. In the illustrated embodiment, thedepression 110 has a generally frusto-conical shape, which convergesinward toward a flat base 114.

[0080] Preferably, the angle of convergence of the depression 110 issmall enough and/or the diameter of the base 114 is large enough toallow the needle to easily find the depression upon passing through theseptum. The diameter of the depression 110 should also be large enoughto provide a sufficient gap between the opening in a needle seatedwithin the depression and the body of the valve member, to allowinfusion medium to flow from the needle with little or no obstructionfrom the valve member body. However, the diameter of the depression 110should not be so large as to result in insufficient support of theseptum against the downward (with respect to the illustratedorientation) force applied by a needle being pushed through the septum46.

[0081] In preferred embodiments, the angle of convergence may be withinthe range of about 30° and about 150° and the diameter of the base 114may be within the range of about 0.125 inch and about 0.5 inch. In theillustrated embodiment, the angle of convergence of the depression 110is about 60° and the diameter of the base is about 0.025 inch. Thedepression 110 is configured to receive a tip of a needle, as describedbelow with respect to FIG. 12.

[0082] The annular recess 104 in the valve member body is configured toreceive a portion of the spring 52, when the inlet structure isassembled as shown in FIG. 4. The valve member 50 may include an annularrib 105 at the outer periphery of the annular recess 104, to help retainthe spring 52 within the recess 104. With the spring seated within therecess 104, a portion of the thickness dimension of the spring is sharedby a portion of the thickness dimension of the valve member body, suchthat the contribution of the spring and valve member to the overallthickness T of the inlet structure is less than the sum of the thicknessdimensions of the spring and the valve member.

[0083] With reference to FIG. 4, when assembled, the spring 52 islocated between the valve member 50 and the interior surface of thebottom of the cup member 44, and is seated within the annular recess 104in the valve member 50 and the annular groove 76 in the cup member 44.The annular recess 104 and annular groove 76 help retain the spring in acentered relation, relative to the valve member 50. The spring istensioned to provide a spring force between the valve member 50 and thecup member 44, to force the valve member away from the cup member 44, inthe direction toward the septum 46. In preferred embodiments, the springforce is sufficient to force the surface 112 of the valve member 50against the septum 46, when the inlet structure valve is in a closedstate. As described above, the rib 100 on the septum 46 is positioned toimprove a seal between the septum 46 and the surface 112 of the valvemember 50, when the valve member is in the closed state by the force ofthe spring 52 against the septum.

[0084] The spring 52 may be made of or coated with any suitable infusionmedium compatible material and may have any suitable structure that iscompressible and provides a restoring force. In preferred embodiments,the spring is selected to provide sufficient spring force to seal thevalve member 50 against the septum 46, when in a closed state as shownin FIG. 4, yet also allow a needle to move the valve member 50 to anopen state allowing adequate flow during a fill, re-fill or withdrawaloperation. In addition, the type of spring 46 is preferably selected tominimize the contribution of the spring to the overall thickness T ofthe inlet structure. Thus, a spring having a relatively low thicknessprofile is preferred.

[0085] In the illustrated embodiment, the spring 52 comprises a wavecompression spring, which provides a suitable spring force and iscompressible to provide a sufficient amount of movement of the valvemember to allow the valve member to seal in a closed position and moveto an open position during a fill, re-fill or withdrawal operation.Other embodiments may employ other suitable springs, preferably of thelow-profile type, including, but not limited to belville, crescent,disc, or conical coil springs. The spring may be made of materials suchas, but not limited to, titanium, titanium alloy, stainless steel,MP35-N, or the like. In other embodiments, other forms of restoringmeans for restoring the valve member 50 to its closed position may beemployed, including, but not limited to a resilient material such asfoam rubber, bellows, dome switch-like mechanism, or balloon, or anelectromagnet, magnet, pneumatic pressure or the like, located betweenthe valve member and the cup member or other suitable locations.

[0086] The filter member 54 is configured to surround the valve member50 and spring 52, when assembled as shown in FIG. 4. With reference toFIGS. 4 and 5, the illustrated embodiment of the filter member 54 isconfigured as an annular ring having an open interior. The filter member54 may be made of or coated with any suitable infusion medium compatiblefilter material, which allows infusion medium to pass there through,including, but not limited to, porous titanium, porous ceramic, PFA,FEP, PTFE, polytetrafluorethylene, Teflon, Gortex, other polymers,polysufone, or woven material, perforated material or the like. Inpreferred embodiments, the filter member 54 is suitably rigid andmaintains a spacing between the septum 46 (with the support ring 48) andthe bottom surface of the cup member 44, to allow the valve member 50sufficient room to move between closed and open positions.

[0087] The filter member 54 is positioned to abut the annular raisedportion 78, along the inner peripheral surface of the filter member,when assembled as shown in FIG. 4. In this manner, the annular raisedportion 78 inhibits the filter member 54 from moving laterally, towardthe inner wall 84 of the cup member 44. Preferably, a spacing ismaintained between the filter element 54 and the inner wall 84, tofacilitate the flow of infusion medium toward the apertures 74 in thecup member 44. In the illustrated embodiment, the spacing between thefilter element 54 and the inner wall 84 is shown as an annular volume116 surrounding the filter element in FIG. 4. The annular volume 116 isin flow communication with the annular groove 80, the apertures 74 andthe indentations 86 in the cup member 44.

[0088] In further embodiments, the filter member 54 may be omitted orreplaced with a structural support for supporting the septum 46 at aspecified distance from the end of the cup member 44 but allowingpassage of infusion medium toward the apertures 74. In such embodiments,a filter (not shown) may be included in or adjacent the apertures 74 orwithin the reservoir housing portion 13 or other portion of the infusionsystem.

[0089] With reference to FIGS. 4 and 5, the illustrated inlet structuremay be constructed by forming components as described above inaccordance with any suitable manufacturing process or processes,including, but not limited to molding, extruding, machining, acombination of such processes, or the like. Once the components areformed or obtained, the filter member 54 may be placed within the cupmember 44, on the surface 88. Also, the spring 52 may be seated withinthe recess 104 of the valve member 50 and also within the groove 76 inthe cup member 44. The support ring 48 may be seated within the recess90 of the septum 46 and placed adjacent the filter member 54, with theannular rib 100 of the septum abutting the surface 112 of the valvemember 50.

[0090] The outer cap 42 may then be threaded over the cup member 44, byengaging the threaded wall 62 of the cap 42 with the threaded outersurface of the cup member and rotating the components relative to eachother. A tool may be engaged with the indentations 64 (or protrusions),to assist in the rotating operation, as described above. By so threadingthe outer cap 42 onto the cup member 44, the inner surface of the end ofthe cap 42 is forced against the rib 96 of the septum 46, to help sealthe septum against the cap 42 and to retain the septum within the cupmember 44, against the force of the spring 52. According to an exampleembodiment, adjustments of the force applied by the cap 42 against theseptum 46 may be made by further threading or unthreading (tightening orloosening) the cap 42 relative to the cup member 44. Such adjustments,in turn, provide the ability to adjust and test valve performancecharacteristics during manufacture. In preferred embodiments, once thedesired performance characteristics are selected by selectivelytightening or loosening the cap 42, the cap is welded to the cup member44, for example, as part of the manufacturing process. In alternativeembodiments, the cap 42 and the cup member 44 may remain non-permanentlycoupled, to allow post-manufacture adjustment.

[0091] In operation, the illustrated inlet structure is configured toprovide a closed state, in which the inlet is sealed against fluid flow(either inward or outward), and an open state, in which the inletstructure receives a needle and allows the fluid to pass through theapertures 74 either to or from the needle. In FIG. 4, the inletstructure is shown in a closed state, wherein two sealing mechanisms(i.e., the septum and the valve) operate to inhibit fluid flow throughthe structure. In alternative embodiments, either one of the two sealingmechanisms may be employed, without the other. In yet furtheralternative embodiments, more than two sealing mechanisms are employed.

[0092] In the FIG. 4 embodiment, the first sealing mechanism is providedby the solid (or sealed slit) nature of the septum 46 and the sealprovided by the septum 46 against the end of the cap 42 and the innerwall 84 of the cup member 44. As described above, the sealing mechanismmay be improved, allowing the thickness T_(S) of the septum to beminimized or reduced, by employing ribs 96 and 102. The second sealingmechanism is provided by the valve member 50, which is forced by thespring 52 against the septum 46. As described above, the sealingmechanism provided by the valve-to-septum abutment may be improved byemploying one or more ribs 100 on the surface of the septum, each ofwhich abuts the valve member 50. Thus, in the closed state as shown inFIG. 4, the inlet structure may provide a reliable seal against fluidflow through the structure, to help seal against unwanted fluid flowinto or out of the infusion device 10 (FIG. 1). In addition, the sealingmechanisms are constructed with components configured to minimize theoverall thickness T of the inlet structure, without compromising sealingfunctions.

[0093] During a fill, re-fill or withdrawal operation, a hollow needle,such as an hypodermic needle, thin catheter or other thin-tubestructure, is inserted into the inlet structure, through the inletopening 24. In embodiments in which the infusion device 10 (FIG. 1) isimplanted in a patient's body, the needle may be inserted through thepatient's skin, at the implant site, to engage the depression 26 in theinlet structure. The needle may be guided by the angle or curvature ofthe depression 26 into the inlet opening 24 and, then, into the septum50.

[0094]FIG. 11 shows a needle 120 that has entered the inlet opening 24and is beginning to pierce the septum 46. The septum 46 may be providedwith a slit, either fully or partially through the body of the septum,to assist the piercing operation. Alternatively, an unslitted septum maybe used with a non-coring needle. As shown in FIG. 11, the needle hasnot passed through the septum and, as a result, the valve member 50remains in the closed state, in which it is forced against the septum bythe spring 52.

[0095]FIG. 12 shows the needle 120, after it has passed through theseptum 46 and has contacted the valve member 50 and forced the valvemember to move toward the end of the cup member 44, against the force ofthe spring 52. In the state shown in FIG. 12, the inlet structure isopen to receive fluid, such as infusion medium, from the needle 120.However, the inlet structure preferably remains sealed from the externalenvironment, by the seal formed between the needle 120 and the septum 46at the interface 122. In this regard, the septum 46 is preferably formedof a material, as described above, that will resiliently mold around theneedle 120 and, more preferably, will do so even after repeated needleinsertions.

[0096] By passing the needle 120 through the septum and forcing thevalve member 50 into an open state, as shown in FIG. 12, fluid may beexpelled or drawn out from an opening 124 in the needle. In someembodiments, the interior of the reservoir may be under a negativepressure relative to the pressure of in the external environment (e.g.,the environment outside of the patient's epidermis). In this manner,during a fill or re-fill operation, the negative pressure within thereservoir may be used to draw or help draw infusion medium from theneedle. In preferred embodiments, the negative pressure of the reservoiris sufficient to draw medium from the needle into the reservoir, withoutrequiring an additional external force to be applied to the medium. Inother embodiments, an external force, such as the force of an hypodermicneedle plunger, may be imparted on medium within the needle, to conveyor help convey the medium from the needle to the reservoir during a fillor re-fill operation. In either case, the reservoir pressure may benegative relative to the implant environment (the environment within thepatient's body, at the implant site), to help reduce the risk ofundesired leakage of medium from the reservoir, into the surroundingimplant environment.

[0097] Fluid exiting the needle 120 enters the volume 126 formed betweenthe valve member 50 and the septum 46. The fluid may then pass throughthe filter member 54 and into the annular volume 116, between the filtermember and the inner wall of the cup member 44. Fluid in the annularvolume 116 is then distributed to the apertures 74, through the annulargroove 80 and indentations 86 in the cup member 44.

[0098] Fluid may be drawn through the apertures 74, for example, by anegative relative pressure within the reservoir housing portion of theinfusion device 10 (FIG. 1). Alternatively, or in addition, the outerdiameter of the valve member 50 may be made close enough to the innerdiameter of the filter member 54 to produce a pressure on fluid withinthe volume 126 to force the fluid through the apertures 74, after theneedle 120 is withdrawn and the spring 52 forces the valve member 50back toward the septum 46. Other mechanisms may be employed to causefluid to pass through the apertures 74 and into the reservoir housingportion of the infusion device, including, but not limited to, pressureapplied to fluid in the needle by, for example, a syringe plunger.

[0099] In this manner, the infusion device 10 (FIG. 1), may be filled orre-filled with a fluid, such as an infusion medium, cleaning medium,testing medium or other medium. In addition, medium may be drawn fromthe infusion device, through the inlet structure, in a similar manner asdescribed above. However, instead of pressure differentials causingfluid to flow from the needle 120 and out the apertures 74, the pressuredifferential is set to cause fluid to flow from the reservoir housingportion of the device, through the apertures 74 and into the opening 124in the needle 120. This may be accomplished, for example, by pullingback on the plunger of a syringe, while the needle 120 holds the valve50 in the open position shown in FIG. 12.

[0100] The distance moved by the valve member 50 between a closed state(FIG. 4) and an open state (FIG. 12) and, thus, the thickness dimensionof the volume 126, is designed to allow sufficient fluid flow from theneedle opening 124 to the filter member 54. However, in preferredembodiments, the contribution of the volume 126 to the overall thicknessT of the inlet structure is minimized. In particular, preferredembodiments of the inlet structure 20 do not require thick volume spacesbetween the valve member and the septum and, thus may be made relativelythin, without compromising the ability to transfer fluid from (or to) aneedle 120.

[0101] To function with such preferred embodiments, the needle 120 maybe configured with an opening 124 that is relatively close to the tip128 of the needle, as compared to typical conventional needles. To helpexemplify that preferred embodiment of the invention, FIG. 13a shows aneedle 120 in accordance with that preferred embodiment, while FIG. 13bshows a typical conventional hypodermic needle 120′, which may beemployed with other embodiments of the invention.

[0102] The needle 120 in FIG. 13a includes a needle opening 124 that islocated relatively close to the tip 128 of the needle and, preferably,is located at the location at which the needle begins to converge towardthe tip 128. In the illustrated embodiment, the needle opening 124 isabout 0.025 of an inch (0.064 cm.) from the tip of the needle and has adiameter of about 0.012 of an inch (0.03 cm.). According to oneembodiment of the invention, the needle opening 124 may be from 0.025 ofan inch to 0.027 of an inch from the tip of the needle and may be in arange from 0.025 of an inch +/−0.020 of an inch. An indentation 125 of adiameter of about 0.026 of an inch (0.066 cm.) may be formed around theopening 124. In preferred embodiments, the indentation abuts or isdirectly adjacent to the converging portion of the needle tip. Infurther embodiments, the edge of the indentation 125 is within adistance from the needle tip 128 equal to about one diameter of theneedle opening 124 and, more preferably, within a distance of the tip128 equal to about one half of the diameter of the needle opening 124.

[0103] To allow close spacing of the needle opening 124 to the needletip 128, the radius of the tip of the needle may be made larger thanthat of typical conventional hypodermic needles. For example, the radiusof the needle tip 128 may be within the range of about one quarter toabout one half of the diameter of the needle. In the illustratedembodiment, the radius of the needle tip 128 is about 0.014 of an inch(0.036 cm.). The needle may be introduced into the patient through anintroducer needle, to reduce trauma to the patient.

[0104] In comparison, one example of a typical conventional needle 120′shown in FIG. 13b includes an aperture 124′ which is located on theshaft of the needle, well above the location at which the needleconverges toward its tip 128′. Conventional hypodermic needles typicallyinclude a length L₁ devoted solely to converging to the tip 128′,requiring the opening 124′ to be located at a relatively great distancefrom the tip 128′ as compared to the distance of the opening 124 fromthe tip 128 of the needle 120 in FIG. 13a. For example, a typicalhypodermic needle may have an opening 124′ located a distance L₂ fromthe tip 128′, where L_(s) is much greater than L₁.

[0105] By using a needle 120 having an opening 124 located relativelynear the tip 128, such as, but not limited to, the needle shown in FIG.13a, embodiments of the inlet structure may be configured with arelatively small overall thickness T, to result in a device 10 having arelatively thin form factor. In particular, such embodiments may includea valve member 50 having a depression 110 which is relatively shallow,for example, within the range of about 0.01 inch to about 0.05 inchdeep. Because the depression 110 may be made relatively shallow, thethickness T_(V) of the valve member 50 (FIG. 10), may be relativelysmall. In this manner, the contribution of the valve member 50 to theoverall thickness T of the inlet structure may be minimized or reduced.

[0106] In addition, by using a needle 120 having an opening 124 locatedrelatively near the tip 128, such as, but not limited to, the needleshown in FIG. 13a, the distance by which the valve member 50 must bemoved to locate the needle opening 124 below the septum and in thevolume 126 between the septum and the valve member is relatively small,as compared to a conventional needle as shown in FIG. 13b. In thismanner, the inlet structure may be configured to accommodate relativelysmall strokes or movements of the valve member 50 in the thickness T (oraxial A) direction of the device and, thus, may be configured with arelatively small thickness in the space in which the valve member 50moves. Thus, the contribution of the space between the septum 46 and theopen position of the valve member 50 (or between the septum 46 and theend of the cup member 44) to the overall thickness T of the inletstructure 20 may be relatively small, as compared to configurationsdesigned for a conventional needle 120′ shown in FIG. 13b.

[0107] Therefore, embodiments of the invention relate to an inletstructure for an infusion device, where the inlet structure isconfigured to operate with a needle having an opening located relativelynear the tip (such as, but not limited to, the needle 120 shown in FIG.13a). Preferred embodiments of the inlet structure are configured with arelatively small thickness in the space in which the valve member 50moves and, thus, a relatively small overall thickness T_(I). Furtherembodiments of the invention relate to a system which includes a needlehaving an opening located relatively near the tip (such as, but notlimited to, the needle 120 shown in FIG. 13a) and an inlet structure ofan infusion device, configured to operate with such a needle.

[0108] Additional embodiments of the invention relate to infusiondevices which include inlet structures as described herein and systemswhich include needles having an opening located relatively near the tip(such as, but not limited to, the needle 120 shown in FIG. 13a) andinfusion devices having inlet structures as described herein. Furtherembodiments relate to inlet structures (and infusion devices and systemsemploying inlet structures) that are configured to operate withconventional needles, but include other aspects of the inventiondescribed herein. Yet further embodiments relate to methods of makingand using the inlet structures, infusion devices and systems describedherein.

[0109] In the embodiments described above, the septum 46 includes asurface facing the valve member 50 which functions as a valve seatagainst which the valve member 50 contacts and seals, when in a closedposition (as shown in FIG. 4). In preferred embodiments, the septum alsofunctions as a seal, to seal and reseal the opening through which aneedle may pass during a fill, refill or fluid withdrawal operation.Another inlet structure embodiment employing a single-piece septum andvalve seat is shown in FIG. 14.

[0110] In FIG. 14, an inlet structure 220 is configured similarly, inmany respects, to the inlet structure 20 of FIG. 4. Components of theinlet structure 220 of FIG. 14 that correspond to similar components inFIG. 4 are labeled with reference numbers that are 200 greater thancorresponding components in FIG. 4. Thus, for example, the inletstructure 220 includes an outer cap 242 (corresponding to outer cap 42in FIG. 4), a cup-shaped member 244 (corresponding to cup-shaped member44 in FIG. 4), a septum 246 (corresponding to septum 46 in FIG. 4), asupport ring 248 (corresponding to ring 48 in FIG. 4), a valve member250 (corresponding to valve member 50 in FIG. 4), a valve spring 252(corresponding to spring 52 in FIG. 4), and a filter member 254(corresponding to filter 54 in FIG. 4). Unless inconsistent with thedescription and illustrations of the FIG. 14 embodiment, thedescriptions of components in the FIG. 4 embodiment are applicable tothe corresponding components in FIG. 14. FIG. 15 shows an exploded viewof the inlet structure 220 of FIG. 14.

[0111] In the embodiment of FIGS. 14 and 15, the septum 246 differs fromthe septum 46 shown in FIG. 4, in that the septum 246 includes a taperedor generally conical surface 247 facing the closed end of the outer cap242 and the inlet opening 224. With reference to FIGS. 14 and 15, thetapered surface 247 forms a relatively thick central region of theseptum, as compared to the outer peripheral region. In the illustratedembodiment, the conical, tapered surface 247 is centrally located andextends radially outward to a radius less than the outer peripheralradius of the septum, beyond which the septum defines a relatively flatouter peripheral surface 249. The center or apex of the conical, taperedsurface is located at the interior end of the inlet opening 224 and maybe flattened or provided with a depression to help receive and guide aneedle during a needle insertion operation.

[0112] As shown in FIG. 14, the septum-facing surface of the outer cap242 has a centrally located, inwardly conical, tapered depression whichmatches and engages the tapered surface 247 of the septum. The inletopening 224 is located at the apex of the conical, tapered depression.The septum-facing surface of the cap 242 also includes an annular,generally flat surface around the conical depression, to engage thegenerally flat outer peripheral surface 249 of the septum. In thismanner, when the cup-shaped member 244 is threadingly coupled to theouter cap 242 and appropriately tightened, the conical, tapereddepression surface on the cap 242 engages the conical, tapered surface247 of the septum 246 at an angle relative to the axis A of the inletopening 224. As a result, tightening of the outer cap 242 and cup-shapedmember 244 results in a force (represented by arrows 251) directedannularly around the inlet opening and angled toward the axis of theinlet opening and, thus toward the path that a needle would take whenpassed through the inlet opening and through the septum. The force 251is directed to help close the septum around the shaft of a needlepassing through the septum along the inlet axis A. The force 251 mayalso help close the slit or needle hole left in the septum, for example,after a needle is removed from the septum.

[0113] Thus, in the embodiment shown in FIGS. 14 and 15, the conical,tapered surface 247 of the septum 246 and correspondingly tapereddepression in the outer cap 242 may be configured to provide a septumsealing force, to help the septum form an effective seal. The generallyflat outer surface 249 of the septum 246 may be arranged to engage acorresponding, generally flat annular surface of the outer cap 242, tohelp center and stabilize the septum 246.

[0114] As noted above, the septum 246 includes a valve-facing surfacethat functions as a valve seat, against which the valve member 250 mayengage and seal. Similar to the septum 46 in FIG. 4, the septum 246 mayinclude one or more annular ribs on the valve seat surface (representedby 300 in FIG. 14), for improved sealing capabilities. In theillustrated embodiment, annular ribs are not located on other surfacesof the septum, such as the surfaces 247 and 249, as the engagement ofthe conical, tapered surfaces may provide sufficient sealingcapabilities. In other embodiments, however, one or more annular ribsmay be located on surfaces 247 and/or 249 to help improve sealingcapabilities, similar to the function of annular rib 96 of septum 46 (ofthe embodiment of FIGS. 4 and 9).

[0115] Also similar to the arrangement shown in FIG. 4, the septum 246includes an annular recess in which the support ring 248 is disposed. Inthe FIG. 14 embodiment, the annular recess and support ring are on theopposite surface of the septum 246 with respect to the conical, taperedsurface 247. The support ring 248 in the FIG. 14 embodiment functionssimilarly to the support ring 48 described above with respect to FIG. 4.However, the support ring 248 includes an annular recess at the outerperiphery of its valve-facing surface, for receiving a portion of thefilter 254. The annular recess helps center and stabilize the componentsrelative to each other.

[0116] The outer cap 242 and cup-shaped member 244 in the FIG. 14embodiment function similarly to the outer cap 42 and cup-shaped member44 described above with respect to FIG. 4. However, the threadedsurfaces of the outer cap 42 and the cup-shaped member 44 do not extendto the bottom (with respect to the orientation shown in FIG. 14) of theinlet structure. Instead, the cup-shaped member 244 is provided with anannular lip 253 extending outward around the closed end of the member244. A gap 255 is provided between the lip 253 and the threads on theouter surface of the cup-shaped member. The lip 253 and gap 255 providesurfaces that are easier to weld, as compared to a threaded surface. Asa result, the cup-shaped member 244 and outer cap 242 may be readilywelded together, once the appropriate degree of tightness is achieved bythreading the two components together.

[0117] In addition, in the embodiment of FIG. 14, the septum is engagedby the open end of the cup-shaped member 244 and is compressed betweenthose two members, upon threadingly tightening the two members together.A gap 257 is provided between the cup-shaped member 244 and the outercap 242, at the septum-end of the cup-shaped member. Upon threadinglytightening the cup-shaped member 244 and the outer cap 242, the septum246 is allowed to deform and flow slightly into the gap 257.

[0118] Yet another inlet structure embodiment is shown in FIG. 16. InFIG. 16, an inlet structure 320 is configured similarly, in manyrespects, to the inlet structure 20 of FIG. 4. Components of the inletstructure 320 of FIG. 16 that correspond to similar components in FIG. 4are labeled with reference numbers that are 300 greater thancorresponding components in FIG. 4. Thus, for example, the inletstructure 320 includes an outer cap 342 (corresponding to outer cap 42in FIG. 4), a cup-shaped member 344 (corresponding to cup-shaped member44 in FIG. 4), a septum 346 (corresponding to septum 46 in FIG. 4), asupport ring 348 (corresponding to ring 48 in FIG. 4), a valve member350 (corresponding to valve member 50 in FIG. 4), a valve spring 352(corresponding to spring 52 in FIG. 4), and a filter member 354(corresponding to filter 54 in FIG. 4). Unless inconsistent with thedescription and illustrations of the FIG. 16 embodiment, thedescriptions of components in the FIG. 4 embodiment are applicable tothe corresponding components in FIG. 16. FIG. 17 shows an exploded viewof the inlet structure 320 of FIG. 16.

[0119] Similar to the embodiment of FIGS. 14 and 15, the embodiment inFIG. 16 includes a septum 346 with a conical, tapered surface 347 and agenerally flat outer peripheral surface 349 which face correspondinglyshaped surfaces on the outer cap 342. Thus, advantages with respect toimproved sealing and stabilization described above with respect to thetapered and generally flat surfaces of the septum and outer cap in FIGS.14 and 15 are applicable to the corresponding components in FIGS. 16 and17.

[0120] Unlike the embodiment of FIGS. 14 and 15, however, the embodimentof FIGS. 16 and 17 employs a valve seat member 361, separate from theseptum 346. The valve seat member 361 may be made of or coated with anysuitable infusion medium compatible material such as, but not limited tosilicon rubber, ethylane propylene, neoprene, latex, Teflon, or thelike. With reference to FIGS. 16 and 17, the valve seat member 361 has agenerally circular, disc-shaped body, with a central opening throughwhich a needle may pass. The valve seat member may be disposed in anannular channel provided in the valve-facing surface of the supportingring 348. In one preferred embodiment, the valve seat member 361 ismolded in place in the supporting ring 348. In other embodiments, othersuitable processes of setting the valve seat member 361 in place may beemployed.

[0121] In the embodiment illustrated in FIGS. 16 and 17, the supportingring 348 has a smaller central aperture than the supporting rings 248and 48 shown in embodiments of FIGS. 4 and 14. As a result, thesupporting ring 348 has sufficient surface area around the centralaperture to provide the annular channel in which the valve seat member361 is disposed. In a further embodiment, the valve seat may be formedintegral with the supporting ring 348, to reduce the number ofcomponents in the structure. The septum-facing surface of the supportingring 348 may be provided with an annular taper 363 around the centralaperture, to help guide a needle tip into the central aperture.

[0122] Embodiments of the invention may employ any one or combination ofaspects described herein for minimizing or reducing the requiredthickness T_(I) of the inlet structure, for minimizing or reducing thecontribution of the inlet structure to the overall thickness of theinfusion device, for improving sealing functions, for improvingoperational life of the inlet structure and/or for providing otheradvantages described herein or inherent from the disclosed structures orprocesses. In one preferred embodiment, all aspects described above areemployed to result in an inlet structure or infusion device with arelatively small thickness, including, but not limited to: the selectionof a convergence angle of the cone-shaped depression 26 to be within therange of about 60° and 180° and, preferably about 150°; a septum havingone or more sealing ribs or a recess for receiving a support ring, toallow the septum to be made relatively thin without compromising sealingor support functions; a cup member having grooves and indentationsformed in its inner surfaces, to improve flow of infusion medium withoutadded structural thickness; a septum and cup-member having matchingconical, tapered surfaces for improved sealing and stabilization; avalve member having a relatively shallow needle-receiving depression orhaving a recess for receiving and sharing thickness dimension with a thespring; and an inlet configuration which accommodates a needle having anopening located near its tip and, thus, employs a relatively shortstroke of the valve member between closed and open states of the valvemember.

[0123] Embodiments of the present invention may incorporate septums withno valve. For example, in embodiments where the main seal is provided bythe septum, the valve may function as a redundant safety system. Thus,in these embodiments, the valve may be eliminated. As a consequence,there may be a corresponding reduction in the height of the assembly orthe septum may be thicker. In addition, embodiments of the presentinvention may employ multilayer septums. For example, septums may bearranged in a star-like fashion, each septum being approximately 45°from the next septum.

[0124] The foregoing description of preferred embodiments of theinvention has been presented for the purposes of illustration anddescription. It is not intended to be exhaustive or to limit theinvention to the precise form disclosed. Many modifications andvariations are possible in light of the above teaching. For example,while some embodiments employ drive mechanisms and/or propellants todrive infusion medium out of the reservoir, further embodiments of theinfusion device may be configured to deliver or limit delivery ofinfusion medium by capillary action, diffusion through a membrane or thelike, without the requirement of a drive mechanism, control electronicsor propellants. In such a configuration, the housing 12 need not includea portion containing a drive mechanism and control electronics. Also,while various embodiments are described above in the context ofimplantable infusion devices, other embodiments of the invention mayemploy aspects discussed above in external infusion devices designed tobe located external to a patient and connected to the patient through acatheter or the like. Furthermore, while various embodiments describedherein include a generally conical-shaped inlet depression to help guidea needle into an inlet opening, other embodiments may includealternative or additional means to help locate an inlet opening and/orguide a needle into the inlet opening. For example, further embodimentsmay include a ring or other suitable pattern of magnetic material (suchas a permanent magnet) disposed around the inlet opening or around theconical inlet depression, where the needle is made of or includesmagnetizable material. In other embodiments, the needle may be made ofor include a magnetic material for magnetically interacting with magnetsor magnetizable material on the inlet structure.

What is claimed is:
 1. An infusion device for delivering infusion mediumto a patient and for receiving infusion medium from a hollow needleduring a fill or re-fill operation, the device comprising: a housinghaving a reservoir portion for containing a volume of infusion mediumand an outlet through which infusion medium may be dispensed; and aninlet structure provided in fluid flow communication with the reservoirportion of the housing, the inlet structure having an inlet opening anda generally cone-shaped depression for receiving and guiding a tip of aneedle toward the inlet opening, the generally cone-shaped depressionhaving an average angle of convergence within the range of about 60° andabout 150°.
 2. An infusion device as recited in claim 1, wherein theangle of convergence of the generally cone-shaped depression is about150°.
 3. An infusion device as recited in claim 1, wherein the inletopening is provided at the apex of the generally cone-shaped depression.4. An infusion device as recited in claim 1, wherein the generallycone-shaped depression has a depth within the range of about 0.02 inchand about 0.09 inch.
 5. An infusion device as recited in claim 1,wherein the generally cone-shaped depression has a depth of about 0.05inch.
 6. An infusion device as recited in claim 1, wherein the inletstructure further comprises: a septum disposed in relation to the inletopening, to seal the inlet opening, the septum having a recess and athickness dimension; and a support member disposed within the recess ofthe septum to support the septum, the support member having a thicknessdimension; wherein, at least a portion of the thickness dimension of thesupport member within the recess overlaps a portion of the thicknessdimension of the septum to reduce the combined thickness of the septumand support member.
 7. An infusion device as recited in claim 6, whereinthe entire thickness of the support member is disposed within the recessin the septum, such that the combined thickness of the septum andsupport member is not greater than the thickness of the septum.
 8. Aninfusion device as recited in claim 1, wherein the inlet structurefurther comprises: a septum having a central portion disposed inrelation to the inlet opening, to seal the inlet opening, the septumfurther having an annular recess disposed around the central portion anda thickness dimension; and a support member disposed within the recessof the septum to support the septum against deformation, the supportmember having a generally rigid annular body with a thickness dimensionand a central opening for allowing a needle to pass through the septumand the support member; wherein, at least a portion of the thickness ofthe support member within the recess overlaps a portion of the thicknessof the septum to reduce the combined thickness of the septum and supportmember.
 9. An infusion device as recited in claim 8, wherein the entirethickness of the support member is disposed within the recess in theseptum, such that the combined thickness of the septum and supportmember is not greater than the thickness of the septum.
 10. An infusiondevice as recited in claim 1, wherein the inlet structure furthercomprises: a septum having a side disposed in relation to the inletopening, to seal the inlet opening; a moveable valve member disposed onthe opposite side of the septum relative to the side of the septum thatseals the inlet opening, the valve member being moveable between a firststate in which the valve member contacts the septum and a second statein which the valve member is spaced from the septum to define a volumespace between the septum and the valve member; and means for imparting aforce on the valve member to urge the valve member against the septum.11. A device as recited in claim 10, wherein the moveable valve memberhas a first surface for contacting the septum when the valve member isin the first state, the first surface of the moveable valve memberhaving a depression for receiving a tip of a needle passed through theinlet opening and the septum, the depression in the first surface of thevalve member having a depth within the range of about 0.01 inch andabout 0.05 inch.
 12. A device as recited in claim 11, wherein thedepression in the first surface of the valve member has a depth of nomore than about 0.03 inch.
 13. A device as recited in claim 10, whereinthe moveable valve member has a first surface for contacting the a tipof a needle passed through the inlet opening and the septum to move thevalve member to the second state, wherein upon the valve member being inthe second state, the distance between the first surface of the valvemember and the septum is no greater than about 0.075 inch.
 14. A deviceas recited in claim 11, wherein the moveable valve member has a secondsurface and a recess in the second surface and wherein the means forimparting a force comprises a spring partially disposed within therecess in the second surface of the valve member.
 15. A device asrecited in claim 10, wherein the means for imparting a force on thevalve member comprises a spring having a generally low profile.
 16. Adevice as recited in claim 10, wherein the means for imparting a forceon the valve member comprises a wave compression spring.
 17. A device asrecited in claim 10, wherein the means for imparting a force on thevalve member comprises at least one of the group consisting of a wavecompression spring, a belview spring, a crescent spring, a conical coilspring, a leaf spring, and an elastomeric fill material.
 18. A device asrecited in claim 10, wherein the moveable valve member has a firstsurface for contacting the septum when the valve member is in the firststate, and wherein the septum includes at least one rib disposed tocontact the first surface of the valve member upon the valve memberbeing in the first state, for improving a seal between the septum andthe valve member upon the valve member being in the first state.
 19. Adevice as recited in claim 18, wherein the at least one rib comprises anannular rib.
 20. An infusion device for delivering infusion medium to apatient and for receiving infusion medium from a hollow needle during afill or re-fill operation, the device comprising: a housing having areservoir portion for containing a volume of infusion medium and anoutlet through which infusion medium may be dispensed, and an inletstructure provided in fluid flow communication with the reservoirportion of the housing, the inlet structure having an inlet opening, aseptum and a support member; wherein the septum has a thicknessdimension and a recess and is disposed in relation to the inlet opening,to seal the inlet opening; wherein the support member has a thicknessdimension and is disposed within the recess of the septum to support theseptum, such that at least a portion of the thickness of the supportmember overlaps a portion of the thickness of the septum to reduce thecombined thickness of the septum and support member.
 21. An infusiondevice as recited in claim 20, wherein the entire thickness of thesupport member is disposed within the recess in the septum, such thatthe combined thickness of the septum and support member is not greaterthan the thickness of the septum.
 22. A device as recited in claim 20,wherein: the septum has a central portion disposed in relation to theinlet opening, to seal the inlet opening; the recess in the septumcomprises an annular recess disposed around the central portion; and thesupport member comprises a generally rigid annular body with a centralopening for allowing a needle to pass through the septum and the supportmember.
 23. An infusion device as recited in claim 22, wherein theentire thickness of the support member is disposed within the annularrecess in the septum, such that the combined thickness of the septum andsupport member is not greater than the thickness of the septum.
 24. Aninfusion device for delivering infusion medium to a patient and forreceiving infusion medium from a hollow needle during a fill or re-filloperation, the device comprising: a housing having a reservoir portionfor containing a volume of infusion medium and an outlet through whichinfusion medium may be dispensed; and an inlet structure provided influid flow communication with the reservoir portion of the housing, theinlet structure having an inlet opening, a septum, a moveable valvemember and means for imparting a force on the valve member to urge thevalve member against the septum; wherein the septum has a side disposedin relation to the inlet opening, to seal the inlet opening; wherein thevalve member is disposed on the opposite side of the septum relative tothe side of the septum that seals the inlet opening, the valve memberbeing moveable between a first state in which the valve member contactsthe septum and a second state in which the valve member is spaced fromthe septum to define a volume space between the septum and the valvemember; wherein the moveable valve member has a first surface forcontacting the a tip of a needle passed through the inlet opening andthe septum to move the valve member to the second state; and whereinupon the valve member being in the second state, the distance betweenthe first surface of the valve member and the septum is no greater thanabout 0.075 inch.
 25. A device as recited in claim 24, the first surfaceof the moveable valve member having a depression for receiving a tip ofa needle passed through the inlet opening and the septum, the depressionin the first surface of the valve member having a depth within the rangeof about 0.01 inch and about 0.05 inch.
 26. A device as recited in claim25, wherein the depression in the first surface of the valve member hasa depth of no more than about 0.03 inch.
 27. An infusion device fordelivering infusion medium to a patient and for receiving infusionmedium from a hollow needle during a fill or re-fill operation, thedevice comprising: a housing having a reservoir portion for containing avolume of infusion medium and an outlet through which infusion mediummay be dispensed; and an inlet structure provided in fluid flowcommunication with the reservoir portion of the housing, the inletstructure having an inlet opening, a septum, a moveable valve membermoveable between a first state and a second state, and means forimparting a force on the valve member to urge the valve member towardthe first state; wherein the moveable valve member has a first surfacefor contacting the septum when the valve member is in the first state,and wherein the septum includes at least one rib disposed to contact thefirst surface of the valve member upon the valve member being in thefirst state, for improving a seal between the septum and the valvemember upon the valve member being in the first state.
 28. A device asrecited in claim 27, wherein the at least one rib comprises an annularrib.
 29. A device as recited in claim 27, wherein: the inlet structurefurther comprises a cup-shaped member in which the septum, the moveablevalve member and the means for imparting a force are disposed; theseptum includes at least one second rib contacting the cup-shaped memberfor improving a seal between the septum and the cup-shaped member.
 30. Adevice as recited in claim 29, wherein the septum comprises a generallydisc-shaped member having an outer peripheral edge and wherein the atleast one second rib comprises a peripheral rib disposed around theouter peripheral edge of the generally disc-shaped member.
 31. A deviceas recited in claim 29, wherein the inlet structure further includes acap member having an inner surface disposed adjacent the septum andwherein the septum includes at least one third rib contacting the innersurface of the cap member for improving a seal between the septum andthe cap member.
 32. A device as recited in claim 32, wherein the septumincludes a central portion disposed adjacent the inlet opening to sealthe inlet opening and wherein the at least one third rib comprises anannular rib surrounding the central portion of the septum.
 33. A deviceas recited in claim 27, wherein the inlet structure further includes acap member having an inner surface disposed adjacent the septum andwherein the septum includes at least one further rib contacting the capmember for improving a seal between the septum and the cap member.
 34. Adevice as recited in claim 33, wherein the septum includes a centralportion disposed adjacent the inlet opening to seal the inlet openingand wherein the at least one further rib comprises an annular ribsurrounding the central portion of the septum.
 35. An infusion devicefor delivering infusion medium to a patient and for receiving infusionmedium from a hollow needle during a fill or re-fill operation, thedevice comprising: a housing having a reservoir portion for containing avolume of infusion medium and an outlet through which infusion mediummay be dispensed; and an inlet structure provided in fluid flowcommunication with the reservoir portion of the housing, the inletstructure having an inlet opening, a septum, a cup-shaped member inwhich the septum is disposed; the septum includes at least one ribcontacting the cup-shaped member for improving a seal between the septumand the cup-shaped member.
 36. A device as recited in claim 35, whereinthe septum comprises a generally disc-shaped member having an outerperipheral edge and wherein the at least one rib comprises a peripheralrib disposed around the outer peripheral edge of the generallydisc-shaped member.
 37. A device as recited in claim 35, wherein theinlet structure further includes a cap member having an inner surfacedisposed adjacent the septum and wherein the septum includes at leastone further rib contacting the inner surface of the cap member forimproving a seal between the septum and the cap member.
 38. A device asrecited in claim 37, wherein the septum includes a central portiondisposed adjacent the inlet opening to seal the inlet opening andwherein the at least one further rib comprises an annular ribsurrounding the central portion of the septum.
 39. A device as recitedin claim 37, wherein the cap member comprises a threaded surface and thecup-shaped member comprises a further threaded surface and wherein thethreaded surfaces of the cap member and the cup-shaped member arecoupled together in a threaded manner.
 40. An infusion device fordelivering infusion medium to a patient and for receiving infusionmedium from a hollow needle during a fill or re-fill operation, thedevice comprising: a housing having a reservoir portion for containing avolume of infusion medium and an outlet through which infusion mediummay be dispensed; and an inlet structure provided in fluid flowcommunication with the reservoir portion of the housing, the inletstructure having a septum and a cap member provided with an inletopening, wherein the cap member has an inner surface disposed adjacentthe septum and wherein the septum includes at least one rib contactingthe inner surface of the cap member for improving a seal between theseptum and the cap member.
 41. A device as recited in claim 40, whereinthe septum includes a central portion disposed adjacent the inletopening to seal the inlet opening and wherein the at least one furtherrib comprises an annular rib surrounding the central portion of theseptum.
 42. A device as recited in claim 40, wherein: the inletstructure further includes a cup-shaped member in which the septum isdisposed; the cap member comprises a first threaded surface and thecup-shaped member comprises a second threaded surface; the threadedsurfaces of the cap member and the cup-shaped member are coupledtogether in a threaded manner.
 43. An infusion device for deliveringinfusion medium to a patient and for receiving infusion medium from ahollow needle during a fill or re-fill operation, the device comprising:a housing having a reservoir portion for containing a volume of infusionmedium and an outlet through which infusion medium may be dispensed; andan inlet structure provided in fluid flow communication with thereservoir portion of the housing, the inlet structure having a septum, acap member provided with an inlet opening, and a cup-shaped member inwhich the septum is disposed; wherein the septum has a surface incontact with the cap member, adjacent the inlet opening, to seal theinlet opening; wherein the cap member comprises a first threaded surfaceand the cup-shaped member comprises a second threaded surface coupled tothe first threaded surface of the cap member in a threaded manner; andwherein the threaded coupling of the first and second threaded surfacesmay be tightened or loosened by rotating the cap member and thecup-shaped member relative to each other, to adjust the seal of theseptum against the cap member.
 44. A device as recited in claim 43,wherein the septum includes at least one rib contacting the cap memberfor improving a seal between the septum and the cap member.
 45. A deviceas recited in claim 44, wherein the septum includes at least one furtherrib contacting the cup-shaped member for improving a seal between theseptum and the cup-shaped member.
 46. An infusion device for deliveringinfusion medium to a patient and for receiving infusion medium from ahollow needle during a fill or re-fill operation, the device comprising:a housing having a reservoir portion for containing a volume of infusionmedium and an outlet through which infusion medium may be dispensed; andan inlet structure provided in fluid flow communication with thereservoir portion of the housing, the inlet structure having a septum, amoveable valve member moveable between a first state and a second state,a spring tensioned to impart a force against the moveable valve memberto urge the valve member toward the first state, a cap member providedwith an inlet opening, and a cup-shaped member in which the septum,valve member and means for imparting a force are disposed; wherein theseptum has a first surface in contact with the cap member and a secondsurface defining a valve seat in contact with the valve member whereinthe cap member comprises a threaded surface and the cup-shaped membercomprises a further threaded surface coupled to the threaded surface ofthe cap member in a threaded manner; and wherein the threaded couplingof the threaded surfaces of the cap member and cup-shaped member may betightened or loosened by rotating the cap member and the cup-shapedmember relative to each other, to adjust the tension of the spring andthe spring force against the valve member.
 47. A system for filling orre-filling an infusion device, comprising: a generally hollow needlehaving a generally hollow interior, a needle shaft terminating in a tipend and an opening on the needle shaft in fluid flow communication withthe interior of the needle, the needle further having a convergingportion between the needle shaft and the needle tip, wherein thedistance between the needle tip and the needle opening is within therange of about 0.01 inch and about 0.05 inch; an infusion device housinghaving a reservoir portion for containing a volume of infusion mediumand an outlet through which infusion medium may be dispensed; and aninlet structure provided in fluid flow communication with the reservoirportion of the housing, the inlet structure including an inlet opening,a septum having a first side disposed in relation to the inlet openingto seal the inlet opening, and a moveable valve member disposed on theopposite side of the septum relative to the first side of the septum,the valve member being moveable between two maximum end points ofmovement respectively defining a first state in which the valve memberis adjacent the septum and a second state in which the valve member isspaced from the septum relative to the first state to define a volumespace between the septum and the valve member; wherein the inlet openinghas a dimension large enough to allow the needle to pass through theinlet opening and through the septum to contact and move the moveablevalve member; wherein the moveable valve member has a first surface forcontacting the a tip of a needle passed through the inlet opening andthe septum to receive a force from the needle to move the valve memberto the second state, wherein upon the valve member being in the secondstate, the distance between the first surface of the valve member andthe septum is no greater than about 0.05 inch.
 48. A system as recitedin claim 47, wherein the moveable valve member has a first surface forcontacting the septum when the valve member is in the first state, thefirst surface of the moveable valve member having a depression forreceiving a tip of a needle passed through the inlet opening and theseptum, the depression in the first surface of the valve member having adepth within the range of about 0.01 inch and about 0.05 inch.
 49. Asystem as recited in claim 47, wherein the distance between the needletip and the center of the needle opening is about 0.025 inch.
 50. Aninfusion device for delivering infusion medium to a patient and forreceiving a hollow needle during a fill, re-fill operation or mediumwithdrawal operation, the device comprising: a housing having areservoir portion for containing a volume of infusion medium and anoutlet through which infusion medium may be dispensed; and an inletstructure provided in fluid flow communication with the reservoirportion of the housing, the inlet structure having a cap member providedwith an inlet opening through which a needle may pass during a fill,re-fill or medium withdrawal operation, the inlet structure furtherincluding a septum disposed on one side of the inlet opening and havinga central portion through which a needle may pass during a fill, re-fillor medium withdrawal operation; wherein the septum includes a taperedsurface facing the cap member and wherein the cap member includes atapered depression for engaging the tapered surface of the septum andimparting a force directed toward the central portion of the septum,upon the septum being pressed against the cap member.
 51. An infusiondevice as recited in claim 50, further comprising a cup-shaped member inwhich the septum is disposed, the cup shaped member having a threadedsurface, wherein the cap member includes a threaded surface configuredto threadingly engage the threaded surface of the cup-shaped member andwherein the septum is disposed between the cup-shaped member and the capmember and is pressed against the cap member upon the cup-shaped memberand cap member being threadingly tightened together.
 52. An infusiondevice as recited in claim 51, wherein: the cap member has a hollowinterior and an inner peripheral surface on which the cap member threadsare located; the cup-shaped member has an outer peripheral surface onwhich the cup-shaped member threads are located; and the cup-shapedmember extends into the hollow interior of the cap member upon thecup-shaped member and cap member being threadingly tightened together.53. An infusion device as recited in claim 50, wherein the taperedsurface of the septum comprises a generally conical-shaped surface andwherein the tapered depression in the cap member comprises a generallyconical-shaped depression.
 54. An infusion device as recited in claim53, wherein the septum further comprises a generally flat, annularsurface around the generally conical-shaped surface.
 55. An infusiondevice as recited in claim 54, wherein the cap member has a generallyflat, annular surface around the generally conical depression, forengaging the generally flat, annular surface of the septum.